Apparatus and Process for Manufacturing Shaped Plastic Reinforced Composite Articles

ABSTRACT

A process for forming a shaped three dimensional article, comprising the steps of deforming an intermediate form ( 10 ), including a plurality of thermoplastic elongated members that are initially movable relative to each other, while displaceably clamping the intermediate form during the deforming in such a way that while a force is applied for deforming the intermediate form, the intermediate form is free to move within a predetermined limit; and optionally at least partially consolidating the thermoplastic elongated members of the intermediate form for forming a three dimensional article having a predetermined orientation of the elongated members. An apparatus including a press ( 32 ) for forming the shaped three-dimensional article is also disclosed.

CLAIM OF PRIORITY

The present application claims priority to, and the benefit of thefiling date of, U.S. Provisional Application Nos. 60/621,463 filed onOct. 22, 2004 (Attorney Docket No. 63863; 1062-041P1); 60/717,965 filedon Sep. 16, 2005 (Attorney Docket No. 63863B; 1062-041P2); 60/718,025filed on Sep. 16, 2005 (Attorney Docket No. 64371; 1062-051P1); and60/725,399 filed on Oct. 11, 2005 (Attorney Docket No. 63863C;1062-041P3), (Express Mail No. EV789808245US), all of which areincorporated by reference.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application is related to concurrently filed, commonlyowned, copending application entitled Improved Polyolefinic MaterialsFor Plastic Composites (Attorney Docket No. 63863D; 1062-41WO1); PlasticComposite Articles and Methods of Making Same (Attorney Docket No.63863E; 1062-41WO2); Improved Microlayer Structures and Methods(Attorney Docket No. 63863F; 1062-41WO3); and Improved Composite Pipesand Method of Making Same (Attorney Docket No. 63863G; 1062-41WO4); allof which are incorporated by reference.

TECHNICAL FIELD

The present invention relates to the manufacture of shaped plasticcomposite articles, and particularly three-dimensional shaped plasticcomposite articles that incorporate an intermediate form that consistsessentially of thermoplastic elongated members.

BACKGROUND OF THE INVENTION

In the shaping of plastic articles from a substantially flat sheet ofplastic, such as by vacuum forming, or thermoforming it is often desiredbut difficult to control wall thickness throughout the resulting formedarticle, particularly as a result of unbalanced flow within the sheet.

In the shaping of three-dimensional articles made from intermediateforms having repeating structural units, such as a fabric woven fromplastic tape, the potential for wall thickness variations is furtherheightened. In particular the ability, in unconsolidated forms such asfabrics woven from a plastic tape, to control the desired resulting wallthicknesses is complicated not only by the possibility of local thinningof individual tapes, but also from the ability of adjoining tapes tomove relative to each other during deformation and result inuncontrollable tape spacing that would affect resulting surface finish,properties or both in the shaped article.

One object of the invention is to provide a mechanism and process forretaining an intermediate form (particularly one that includes aplurality of elongated members) so that controlled deformation of theform occurs upon application of a pressure to it.

SUMMARY OF THE INVENTION

The present invention relates to a process for forming a shaped threedimensional article, comprising the steps of deforming an intermediateform, including a plurality of thermoplastic elongated members that areinitially movable relative to each other, while displaceably clampingthe intermediate form during the deforming (i.e., clamping theintermediate form in such a way that while a force is applied fordeforming the intermediate form, the intermediate form is free to movewithin a predetermined limit (for example, lateral slippage of adistance up to about 20%, 40%, 60% or higher of the total draw depth ofthe deformed intermediate form) relative to the structure that performsthe clamping function); and at least partially consolidating thethermoplastic elongated members of the intermediate form for forming athree dimensional article having a predetermined orientation of theelongated members. The invention also relates to an apparatus forforming a shaped three dimensional article that is configured to permitdisplacement (e.g., lateral slippage) of the intermediate form duringdeforming. The process and apparatus of the present invention provides aunique approach toward balancing flow within a plastic intermediateform, especially forms that are made from thermoplastic tapes.

DESCRIPTION OF THE DRAWINGS

FIG. 1A is a plan view illustrating a device for shaping an intermediateform.

FIGS. 1B-1D illustrate steps that employ the device of FIG. 1A.

FIG. 1E is another approach to a device for shaping the intermediateform.

FIG. 2 is a perspective view of an example of a mounting frame useful inthe present invention.

FIGS. 3A and 3B are side sectional views through a tooling assemblyuseful in accordance with the present invention, respectively in theopen starting position and during a deforming operation.

FIGS. 4A and 4B are side sectional views through an optional secondarytooling assembly useful in accordance with the present invention,respectively in the open starting position and during a secondarydeforming operation.

FIG. 5 is a perspective view of an example of an apparatus for carryingtooling assemblies in accordance with the present invention.

DETAILED DESCRIPTION OF THE INVENTION

The present invention is predicated upon the discovery of a uniqueapproach to the manufacture of three dimensional articles, andparticularly three dimensional intermediate forms that are at leastpartially consolidated for fabricating an article, such as one adaptedfor incorporation into a shaped composite that includes the intermediateform as a polymeric (and more particularly a thermoplastic polymeric)reinforcement material. The present invention, though in one aspect itcontemplates improved manufacturing processes, also contemplatesarticles produced by the process, and machines useful in the process.Articles having relatively complex geometries may be successfully madein accordance with the present teachings, such as articles requiring arelatively deep draw, as well as articles that have rounded or evensquare or other sharp corners.

In general, the present invention addresses important needs in the artby providing a process including the basic steps of shaping andconsolidating an intermediate form that includes a plurality ofaggregated elongated members (particularly ones that consist essentiallyof a thermoplastic material). As will be appreciated with reference toSer. No. 60/621,463, entitled: “PLASTIC REINFORCED COMPOSITES”, filedOct. 22, 2004 (Attorney Docket No. 63863; 1062-041P1) (incorporated byreference herein), and U.S. Provisional Application Ser. No. 60/717,965,filed Sep. 16, 2005 (Attorney Docket No. 63863B; 1062-041P2), entitled:“PLASTIC REINFORCED COMPOSITES” (incorporated by reference herein) andU.S. Provisional Application Ser. No. 60/725,399 (Attorney Docket No.63863C; 1062-041P3), by “elongated member”, it is generally meant amember that has one of its dimensions (e.g., length) that is longer thanat least one other dimension (e.g., width, height, thickness, ordiameter), particularly, the length of an elongated member here insubstantially greater (e.g., by a factor of at least 10 or higher) thanthe width or height. Accordingly, elongated members herein couldinclude, but are not necessarily limited to a member selected fromfibres, rods, cords, yarns, tapes, filaments, straps or any combinationthereof. As can be appreciated from the above, in a number of aspects,films may also be contemplated as within the meaning of “elongatedmembers”. Small scale members may also be possible, such as whiskers orplatelets. Though “elongated member” is regarded broadly herein, itshould be recognized that particularly preferred forms of the elongatedmember specifically will include one or more of yarns, tapes, fibres andfilaments. A highly preferred elongated member is in the form of a tape.

In addition, it should be appreciated that elongated members of thepresent invention typically will have been processed for achieving aninitial morphology, and specifically an initial orientation state (e.g.,it is monoaxially stretched, biaxially stretched, or otherwisestretched, such as in accordance with the proportions specified herein).Among the many unique advantages obtainable using the subject matterdisclosed herein is the ability upon conclusion of processing, andespecially in finished articles, to realize a substantial preservationof the initial morphology within the elongated member. Accordingly, forexample, upon processing, molecular orientation of the elongated memberis substantially preserved from its initial state (e.g., at least about75% of the initial orientation of the elongated member remains).

Accordingly, elongated members herein could include, but are notnecessarily limited to a member selected from fibres, rods, cords,yarns, tapes, filaments, straps or any combination thereof. Small scalemembers may also be possible, such as whiskers or platelets. At leastpartially along the length of the elongated members, the members couldbe fully densified, partially densified (e.g., foamed), perforated,corrugated, twisted, or any combination thereof.

The dimensions of the elongated member typically could be such that itenables the member to be handled manually. More particularly, however,the elongated member will be dimensioned so that it is capable of beingmachine-handled for processing it into the intermediate form. Forexample, one specific illustration of the present invention envisions anelongated member, such as a yarn, tape, fibre or filament, that has athickness, width or both no larger than about 1 cm, more specifically nolarger than about 0.5 cm, and even more specifically no larger thanabout 1 mm. For example, one approach is to employ an elongated membersuch as a yarn, tape, fibre or filament that has a width of less than 5mm, and a thickness of less than 1 mm and more specifically less than0.5 mm (e.g., about 0.01 to 0.25 mm).

The elongated member may be a monolithic. It may be a single material, amulti-layer material or a combination thereof. A typical geophysicaltextile manufactured from polypropylene tapes would be an example of afabric woven from such elongated members. The elongated member may haveproperties or other characteristics that differ along a dimension of themember. In one aspect, the elongated member may include a first surfaceportion and a second portion that adjoins the first portion, wherein thefirst portion and the second portion differ in composition,polydispersity, morphology (e.g., crystallinity, orientation or both),melt rate, or any combination thereof. For example, one specificapproach envisions at least one elongated member of a firstthermoplastic material and having a surface portion capable of meltingprior to an adjoining oriented portion.

As discussed in Ser. No. 60/621,463, entitled: “PLASTIC REINFORCEDCOMPOSITES”, filed Oct. 22, 2005 (Attorney Docket No. 63863; 1062-041P1)(incorporated by reference herein), and U.S. Provisional ApplicationSer. No. 60/717,965 filed Sep. 16, 2005 (Attorney Docket No. 63863B;1062-041P2), entitled: “PLASTIC REINFORCED COMPOSITES” (incorporated byreference herein), and U.S. Provisional Application Ser. No. 60/725,399(Attorney Nocket No. 63863C; 1062-041P3), at least one elongated memberis processed to make an intermediate form, such as an intermediate formselected from a winding form, a knit form, a braided form, a randomlydispersed form or any combination thereof. As referenced herein theintermediate form will typically include a plurality of repeatingstructural units. For example, an intermediate form might include aplurality of repeating structural units arranged to define a pattern,such as a plain or a twill weave (such as a herringbone, a tweed, ahoundstooth, a plaid or other twill), a lace, a satin, or anycombination thereof. Examples of particular weaves include weaves thathaving a pattern warp elongated member running over and then under aweft elongated member in a warp/weft proportion ranging from 1/1 to 14/2(e.g., 2/1, 2/2, 3/1, or otherwise). Thus, still more particularexamples of weaves include, without limitation, a 2/1 twill, a 2/2twill, a crowfoot satin, a 2/2 basketweave, a 5H satin, a 8-H satin, orotherwise. Individual structural units of the form may be disposed inany of a number of possible configurations relative to each other. Forexample, overlapping units may be generally perpendicular to each other.However, other angles of weave may also be employed as desired. Oneattractive benefit obtainable in accordance with the present inventionis that the intermediate form can be processed so that the resultingshaped article generally retains the orientation of the repeatingstructural units relative to each other.

Prior to any step of shaping, typically, adjoining structural units aremovable relative to each other within an intermediate form. One approachto achieving this is to form the intermediate form, but not subject itto a consolidating processing step by which adjoining structural unitswill become irreversibly joined together, such as by gluing, melting,fastening or otherwise assembling the units. Accordingly, at a timeprior to commencement of deforming in accordance with the process stepsof the present invention, it is particularly desirable the intermediateform not be consolidated, such as by heating to a temperature above themelting point of at least one of the materials in the form to cause thematerial to melt and fuse, and effectively weld with adjoining units.

Intermediate forms may include or consist essentially of a single layer(which optionally may include one or a plurality of patterns). Anintermediate form that includes a plurality of layers (which optionallymay include one or a plurality of patterns) over some or all of theirrespective surfaces, is also contemplated. For example, the number oflayers in the intermediate form may range from about 1 to 100 or more(e.g., 2 to 60, 5 to 50, 10 to 40, greater than 10, greater than 20 orotherwise). Accordingly, it is envisioned that the intermediate form, inan unconsolidated state may have a thickness as small as the thicknessof a single elongated member in it, but may be greater, such as on theorder of about 0.25 mm. to about 2.5 cm or larger. In the consolidatedstate, accordingly, it is envisioned that the intermediate form mayresult in a thickness of about 0.8 mm or smaller to about 1.5 cm orlarger, for example about 0.1 to 0.8 cm or more specifically about 0.3to 0.5 cm.

If a plurality of layers is employed, it is possible that one or morelayers are different from each other in one or more respect, such asmaterial type, composition of the elongated member, heat treatment ofthe elongated member, width of the elongated member, pattern type,whether the layer is consolidated or not, the presence of a film layer,thickness, morphology, or any combination thereof. To illustrate, it ispossible that at least one first layer selected from a film, a coating(e.g., a solvent coating, an extrusion coating or otherwise), aintermediate form, a winding form, a knit form, a braided form, arandomly dispersed form or any combination thereof adjoins at least onesecond layer selected from a film, a coating (e.g., a solvent coating,an extrusion coating or otherwise), an intermediate form, a windingform, a knit form, a braided form, a foam form, a randomly dispersedform or any combination. As indicated, at least one of the plurality oflayers may be consolidated in this illustration. It may also be possiblethat a charge of flowable unformed or formed (reinforced orunreinforced) plastic material may be placed over the exterior of theintermediate form or between adjoining layers, whether over the entirearea of the form or a pre-selected portion of it. In this regard, it ispossible to realize a flowable phase that can locally be fullydensified, without the need for a complete layer to be employed in thatvicinity. It will also be appreciated from the above that portions ofone or more of the layers can be selectively omitted or otherwisemodified so that variations in wall thickness are achieved or localregions of the article are selectively modified.

Ordinarily, the elongated members will be a polymeric material andparticularly a thermoplastic material. One particularly preferred classof thermoplastic materials will include at least one polyolefin (e.g,polypropylene, or propylene-ethylene copolymers), such as a polyolefinavailable from The Dow Chemical Company under, for instance, thedesignations VERSIFY™ or INSPIRE®. Additional examples of materialsuitable for the elongated members are disclosed in Ser. No. 60/621,463,entitled: “PLASTIC REINFORCED COMPOSITES”, filed Oct. 22, 2004 (AttorneyDocket No. 63863; 1062-041P1) (incorporated by reference herein), andU.S. Provisional Application Ser. No. 60/717,965, filed Sep. 16, 2005(Attorney Docket No. 63863B; 1062-041P2), entitled: “PLASTIC REINFORCEDCOMPOSITES” (incorporated by reference herein), and U.S. ProvisionalApplication Ser. No. 60/725,399 (Attorney Docket No. 63863C;1062-041P3).

The polymeric material of the elongated members may be a homopolymer, acopolymer, a blend or some other admixture of polymers. For example, apolypropylene homopolyer may be employed. Alternatively, or in additionto the polypropylene homopolymer, an example of a copolymer include twoor more different polyolefins, e.g., a polypropylene/polyethylenecopolymer. Other examples of materials suitable for use in the presentinvention as elongated members include tapes or yarns disclosed in U.S.Pat. Nos. 5,993,711 and 6,045,923 (assigned to Lankhorst Indutech B.V.),incorporated by reference. According to the former, the profile of theelongated member may include one or more longitudinal ribs and/orlongitudinal grooves on one or more surfaces. According to the latter,it is possible that an elongated member may include a central layerprepared from a blend of high density polyethylene and one or more otherpolyolefins, whereby the amount of high density polyethylene ispredominant, i.e. more than 50% by weight. More in particular, thecentral layer is prepared from a blend of 50 to 90 wt. % of high densitypolyethylene (>940 kg/m³) and 10 to 50 wt. % of (linear) low densitypolyethylene (<925 kg/m³), very low density polyethylene (<910 kg/m³),or combinations of these products. Additionally an amount ofpolypropylene may be present to improve the strength of the material.

The materials of the present invention may offer a range of materialproperties. Without limitation, by way of example, materials inaccordance with the present invention may exhibit a modulus ofelasticity of at least about 13 GPa, and more specifically at leastabout 18 GPa, as measured by ASTM D-638 and a tensile strength of atleast about 150 Mpa, and more typically at least about 300 MPa, asmeasured by the following ASTM test method D-638.

In instances when the intermediate form is a single layer, as well as ininstances when it is desired to have a plurality of layers as part of anintermediate form, one or more layers may be processed for preventingseparation of individual structural units, the respective layers, orboth. For example, for a single or multi-layer form, one or more of thelayers may be secured (and optionally secured to each other for amulti-layer form) in a suitable manner, such as by thermally joining thestructural units along at least a portion of one, two or more of theedges of the form. Other approaches to processing may be employed, suchas a mechanical step (e.g., crimping, fastening, stapling, riveting,stitching or otherwise), an adhesive joining step (e.g., with a drop orbead of adhesive, a tape or otherwise), or a combination. In this mannerit is possible to readily handle the intermediate forms, such as fortransport, storage, placement in a tool cavity or otherwise, whilereducing the likelihood that individual structural units will becomeseparated to the extent that the intermediate form integrity iscompromised.

One of the advantages of the present invention is derived from therecognition that, when employed, typical oriented polymeric materialsuseful for the elongated members of the present invention generallypossess a thermal processing window within which it is possible todeform the material but also within which the material retainssubstantially all of its microstructural orientation, therebysubstantially preserving its mechanical characteristics as a result ofprocessing according to steps of the present invention.

The present invention accordingly affords a convenient and reliable wayto operate within the thermal processing window of the material, thuspermitting for predictable and reproducible characteristics in theresulting articles.

As indicated, for fabricating the articles in accordance with thepresent invention, the intermediate form is provided and handledaccording to a process by which relatively precise control is exercisedover the deformation of the form. Desirably, as the intermediate form isdeformed, care is taken particularly to control the wall thickness ofthe resulting three-dimensional form, the orientation of the elongatedmembers relative to each other within the resulting three-dimensionalform, the molecular orientation of the molecule polymer of the elongatedmember, or any combination thereof.

It may be possible herein to employ an operation by which theintermediate form, prior to shaping and consolidating, is rigidlysecured (e.g., clamped at, near or along any edges. However, aparticularly preferred approach involves supporting the intermediateform during shaping so that the form is displaceable (e.g., affordsslippage of the form relative to any holding tool) during deformation.By way of illustration, with reference to FIGS. 1A-1D, it is envisionedthat an intermediate form 10 will be mounted within a suitable structure12 (e.g., frame). A shaping tool 14 will deform the intermediate form 10(e.g., against a die 16) effectively resulting in at least one shapedregion 18 and a periphery region 20 generally adjoining (e.g., externalon the shaping region. Typically the structure 12 incorporates one ormore biasing members 22. Any biasing members employed typically areselected and located so that they are capable of applying a biasingforce in response to a force realized by an intermediate such form whilethe form is being deformed. In this regard, such biasing mechanismtypically will be adapted for providing a biasing force in a directionparallel to the force of any deforming tool (e.g., as in FIG. 1E). Itmay also be adapted for providing a biasing force in a direction normalduring a cycle to the deforming tool force (combinations of the two mayalso be employed). The biasing members may be connected directly to theintermediate form, to the forming apparatus, to a mounting frame (asdescribed herein) or to some other structure adapted for co-acting withthe intermediate form for controlling displacement during deformation ofthe intermediate form. Biasing may be achieved using any suitablemechanism. Examples include springs, solenoids or other electromagneticdevices, pistons, any combination thereof, or another like work memberthat is resilient, reciprocates, or both.

An example of one particular approach to shaping of the intermediateform (whether single layer or multi-layer) involves the employment of aresilient (e.g., spring-biased) structure, such as a spring-loadedframe, that carries the intermediate form 10, whether or notconsolidated. For example, a shaping tool is brought together with a die22, with a frame-mounted form therebetween. The resiliency of the formholding structure helps to avoid thinning of the form that wouldnormally occur upon forming without the frame, and thus helps to resultin a shaped intermediate form that includes a substantially constantwall thickness and smooth, ruck-free exposed surface throughoutsubstantially the entirety of the usable portion of the resulting form.

It should be appreciated that various configurations of tooling may beemployed for affording the desired combination of holding anddisplacement necessary for successful deformation. For example, oneparticular approach is shown schematically in FIG. 1E, where the frameis itself resiliently mounted, (e.g., by a spring), so that theintermediate form is shaped while allowing flow of the structural unitsto maintain wall thickness during application of pressure. The resilientmounting can be such that the frame is suspended by one or more springs(e.g., the weight of the frame and any other optional force displaceablyclamps the intermediate form), the frame is mounted so that it is biasedtoward the intermediate form during deformation, or a combinationthereof.

It should be appreciated that for multi-layer forms where each layer isable to move over and relative to each other (e.g. sliding independentof each other), the present apparatus may be adapted for maintaining theamount of the movement consistent throughout the form under all loads.

The general approach of the present invention is described in furtherdetail with reference to FIGS. 2-5. Pursuant to such approach, as withFIGS. 1A-1E, conditions are selected for processing the intermediateform during deformation so that controlled deformation within the shapedregion is achieved, and more specifically, relatively uniform wallthickness is obtained where desired, orientation of the elongatedmembers relative to each other is generally preserved, extremedeviations of morphology, crystallinity or both (and resultingproperties) of oriented polymers used in the intermediate form issubstantially avoided, a smooth, ruck free exposed surface results overgenerally the entirety of the shaped region, a depth of draw ratio (therelationship of depth to width of a part) of about 0.1:10 to about 5:1(e.g., about 1:1) is realized, layers of a multi-layer intermediate formare allowed to move relative to each other, damage of the elongatedmembers due to excessive elongation is substantially avoided, or anycombination thereof (preferably a combination of all of the above). Forexample, one particular approach is to control the forces that hold theintermediate form during deformation. That is, described generallyrelative to FIGS. 1A-1E, the force is selected and varied as necessarysuch that the periphery region of the intermediate form undergoes atleast some displacement in response to the forces exhibited duringshaping. For sake of illustration, reference to FIGS. 3A and 3B showdisplacement in the form of lateral slippage, that can be seen by thelateral movement of a Point A on the intermediate form relative to afixed reference point X.

One specific example of a system for permitting displacement of theperipheral region in accordance with the present invention isillustrated with reference to the tooling of FIGS. 2-4, particularly asemployed (without limitation) in the apparatus described generally inFIG. 5. As seen, for aid in handling of the intermediate form, theintermediate form may be positioned in a suitable carrier frame 26. Byway of example, without limitation, FIG. 2 illustrates a carrier, thatincludes at least one carrier member, and more specifically a pluralityof separable co-acting carrier members, such as a first carrier member28 and a second carrier member 30. Though other structures are possibleby which the first carrier member and the second carrier member areconfigured for receiving the intermediate form (e.g., they may be ofsimilar dimensions for opposing each other about their peripheries), oneattractive approach involves employment of carrier members each ofdifferent dimensions, such as for permitting nesting one of carriermembers in the other, with the intermediate form located between them.With particular reference to FIGS. 3A and 3B, one such approach is toform a receiving structure (e.g., a well, a groove, ledge or the like)in one of the carrier members, into which a protuberance (e.g., a pin, aflange, a wall or the like) of the other member can penetrate. Ingeneral, however, the structure of the co-acting carrier members will besuch that when the intermediate form is placed in the carrier, theintermediate form will not be fixed in place but will be displaceable(e.g., by lateral slippage) in response to a deformation force.

Typically, where the carrier is adapted to carry the intermediate formgenerally about at least a portion of entire periphery region 20, thecarrier frame 26 will be adapted to have an opening through thedeformation tool can pass during processing. The intermediate form maybe carried by the carrier so that the form is in contact with thecarrier over some or all of the carrier. Though the embodiment of FIGS.2A and 2B show an enclosed structure, it is also possible that thecarrier frame is divided into a plurality of laterally separatecomponents. The separable co-acting carrier members optionally may bephysically connected to each other, such as by one or more pivotalmembers (e.g., a hinge), fastener, magnets, a combination thereof or thelike.

Turning to the drawings of FIGS. 3A and 3B, taken with reference also toFIG. 5 (showing one example of a press 32), there is shown an approachby which the intermediate form can be displaced during deforming. Asillustrated generally, deforming will be achieved by the use of theshaping tool (e.g., a punch 34), which will act against an opposingshaping tool (e.g., die 36). A blank holder 38, having an exposed wallsurface 40 is disposed adjacent to the deformation tooling (e.g.,outside the perimeter of the punch 34, the die 36, or both), and can bemounted for independent movement relative to the punch 34, the die 36,or both. In the embodiment shown, the punch 34, the die 36, or both areremovably separable from respective platens or other support structure44 and 46 (e.g., it can be removably held in place by a vacuum, byfasteners, or the like). It is also possible that the tool and platenare integrated into a single structure. Further, it is possible that thewall surface may be dimensioned or otherwise configured so that it bearsagainst one or more of the carrier members 28 or 30.

As indicated, mounted for translation independently of the shapingtools, and for displaceably holding the intermediate form duringdeformation will be the blank holder 38. Preferably, the blank holder 38is configured so it does not rigidly fix the intermediate form duringdeformation. In this regard, the blank holder 38 may include one or moreprotuberances 42 (e.g., an annular protuberance) that is adapted forcontacting and displaceably holding the intermediate form duringdeformation. Such contact with the intermediate form may be incombination with the holding of the carrier frame 26, or independent ofany carrier frame contribution. In another embodiment (not shown), theblank holder is configured so that instead of or in addition to directlycontacting the intermediate form, it bears against the carrier frame.

The blank holder 38 may be independently mounted in any suitable manner.It has been found, however, that an approach by which the blank holder38 is carried in accordance with the above teachings helps to realizethe desired flow of the intermediate form within the apparatus duringdeformation. That is, the blank holder (alone or in combination with thecarrier frame) effectively constitutes a resilient frame assembly thatallows flow of the individual structural units of the intermediate formto maintain wall thickness during application of pressure. The resilientmounting can be achieved in a number of ways. For example, as described,the blank holder may be suspended by one or more springs (e.g., theweight of the blank holder and any other optional force displaceablyclamps the intermediate form), the blank holder may be mounted so thatit is biased toward the intermediate form during deformation, or acombination thereof.

One particular preferred approach, as shown in FIGS. 3A and 3B, and FIG.5 shows an approach by which the blank holder 38 is vertically suspendedby one or more shafts 48 along which the blank holder 38 may be fixed orfreely moveable. One or more biasing members (e.g., springs) 50 arelocated for biasing the blank holder 38 toward the intermediate form(not shown in FIG. 5). The biasing members are selected so that theyexert a force toward the intermediate form sufficient to displaceablyengage the intermediate form (and optionally any carrier frame)sufficient to permit the desired amount of flow of the intermediate formacross the engaging surfaces of the blank, the carrier frame or both,during deformation, while at the same time resisting the deformationforces so that the intermediate form remains sufficiently secured sothat deformation of the intermediate form can occur.

Selection of the biasing force thus can be accomplished by considerationof the desired characteristics of the resulting shaped intermediateform. Thus it is possible that the resulting shaped form, over a rangeof depth of draw ratios, will realize a predetermined wall thicknessthroughout the shaped form, orientation of the elongated membersrelative to each other will be generally preserved, extreme deviationsof morphology, crystallinity or both (and resulting properties) of anyoriented polymers used in the intermediate form will be substantiallyavoided, a smooth, ruck free exposed surface results over generally theentirety of the shaped region will occur, a depth of draw ratio (therelationship of depth to width of a part) of about 0.1:10 to about 5:1(e.g., about 1:1) can be realized, layers of a multi-layer intermediateform are allowed to move relative to each other, and damage of theelongated members due to excessive elongation is substantially avoided.

Other factors may be taken into account in the selection of the biasingforce. Alternatively, a biasing force may be selected and one or moreprocessing parameters may be varied in response to the selected biasingforce. For example, without limitation, it is also possible to vary therate of deformation tool travel, vary the load within a cycle, vary thetemperature during the cycle, vary the number of load cycles or anycombination thereof.

Typically, the shaping that will occur during steps represented by FIGS.3A and 3B will be performed at an elevated temperature, e.g., atemperature above room temperature that affords softening of thematerial of the intermediate form, and potentially at a temperatureabove the melting point of the material on the outer surface ofelongated members in the intermediate form. Thus, the temperature ofcomponents of the shaping tooling, the platens, any other associatedcomponents of the apparatus, or any combination thereof, may becontrolled as desired. The temperature of two or more components may beindependently maintained. For example, the platen 44 may be heated orchilled for heating or cooling a shaping tool (e.g. punch 34). A thirdplaten 52 may be included for heating or cooling the shaping tool (e.g.,punch 34) when it is in a retracted position. The opposing shaping tool(die 36) also may be heated or cooled. For example, the second platen 46may be adapted for cooling or heating the shaping tool (e.g., die 36)positioned in it. As desired, insulation 54 may be employed betweencomponents of the apparatus for maintaining discrete thermal zones. Itshould be appreciated that during any deforming step the temperature ofthe intermediate form may be kept substantially constant for one or morepredetermined periods of time (e.g., for at least about 5 seconds toabout one hour, and more preferably about 30 seconds to about 5 minutes;longer or shorter times being possible also). It may also be varied overa range of temperatures for achieving the desired characteristics.Further the intermediate form may be pre-heated to a predetermined firsttemperature and maintained at that temperature during deforming, orheated or cooled to a different temperature during deforming.

In accordance with the above, with reference to FIGS. 3A and 3B, it istherefore seen that deformation of an intermediate form can beaccomplished by loading the intermediate form 10 into the carrier frame26, which is then located so the intermediate form is between opposingportions 34 and 36 of the shaping tool. Load is applied to theintermediate form by advancing the shaping tool portions toward eachother. The blank holder 38 (e.g., using protuberance 42) will engage theintermediate form, along with any engagement contributed by the carrierframe 26. It can be seen that the blank holder 38 can be adapted (e.g.,through its dimensions, operation parameters, or otherwise) so that theblank holder engages the intermediate form at any desired time. Forexample, the blank holder 38 may initially engage the intermediate formfor resisting a deformation load before, simultaneously with or afterwhen the application of the deformation load is commenced.

It can be seen that upon deformation load being applied, and at leastafter commencement of deformation, the periphery region of theintermediate form will be held by the blank holder 38. The biasingforce, however, will permit the periphery region to translate laterally.This is illustrated by showing the relative translation of referencepoint A relative to reference point B in FIGS. 3A and 3B.

The controlled displacement of the intermediate form during deforminghelps to manage the amount of the intermediate form material that entersthe shaped region, helping to avoid excess material that would be proneto folding or creasing. Further, during this step of deformation,particularly under conditions of elevated temperature and pressure fromthe shaping tool, it is like that consolidation of the intermediate formwill occur. Thus, it can also be seen that, if desired, a separate stepof consolidating the intermediate form before shaping can be obviated.Consolidation may be performed in any suitable manner and may beperformed in a single stage operation or as part of a plural stageoperation. In the course of consolidation, an intermediate form thattypically is initially drapable upon itself (e.g., the form itself ispliable, adjoining structural units are movable relative to each other,or both) is consolidated, the form will become at least semi-rigid,preferably so that it is capable of supporting its own weight. It willbe typical that upon shaping and consolidation, the forms of the presentinvention will be capable of long term shape retention, e.g., atambient, greater than 2 weeks, more specifically greater than one month,and even more specifically greater than 3 months. In this manner, it iscontemplated that a form manufacturer can generate an inventory offorms, which can then be stored for an extended period until needed forassembly into a composite. Consolidated forms, particularly those thatinclude a polyolefin as its major constituent, typically will exhibit aconsolidated density ranging from about 0.75 to about 0.9 g/cm³, andmore specifically about 0.83 g/cm³. It is also preferred that theconsolidated forms exhibit a density of at least about 80% oftheoretical density, more preferably a density of at least about 90% oftheoretical density (e.g. higher than 95% of theoretical density, suchas at least 99% of theoretical density).

The consolidating processing step effectively will irreversibly joinadjoining structural units together, and thus consolidating may be doneby a step of gluing, melting, fastening or otherwise assembling theunits. One particular approach made convenient by the present inventionis to heat the intermediate form to a temperature above the meltingpoint of at least one of the materials in the form to cause the materialto melt and fuse, and effectively weld with adjoining units.

The heating step may be performed using any of a number of approaches.For example, it is possible that the form is pre-heating remotely beforedeformation and delivered to the deforming apparatus at an elevatedtemperature, whereupon deformation pressure is applied. In addition, oras an alternative to the preheating step, heating may occur at or withinthe deforming apparatus. For example, a die, a punch, a combinationthereof or another tool for deforming the form can be preheated. In oneapproach, if off-line pre-heating is employed, the temperature withinthe intermediate form may be raised to its requisite processingtemperature within the tool.

Any heating step in accordance with the present invention may beperformed by conduction, convection, radiation or any combinationthereof. An oven may be used as a heat source. A radiofrequency heatsource, a microwave heat source or both may also be used. Heating may bedone in an inert atmosphere, in air, or in another suitable atmosphere.Further, heating steps may include a plurality of steps each performedat a different temperature, each performed under application of adifferent pressure, or a combination thereof.

By way of example, without limitation, for a polyolefin basedintermediate form, a preheat step (if employed), may be performed byheating the intermediate form in the absence of an applied deformationload to a temperature of at least about 60° C., and preferably belowabout 120° C. (e.g., about 100° C.). This may be maintained for severalminutes, or possibly even a day or longer (e.g., about 0.5 to about 20hours). Thereafter, a deformation load may be applied, preferably whilethe intermediate form is subjected to heat (such as from about 120 to160° C. (e.g., about 140° C.) or higher), such as that for realizing adeformation pressure of about 10 to about 200 Bar (e.g., about 20 toabout 140 Bar, and more specifically at least about 80 Bar). Theelevated temperature and pressure is maintained for about 1 to about 10minutes, and more specifically about 3 to about 5 minutes (e.g., about 4minutes) so that consolidation and deformation may occur. It should berealized that longer or shorter times, and/or higher or lower pressuresmay be employed depending upon the size of the intermediate form, withthe above ranges being generally applicable for an intermediate formthat is consolidated to a thickness of about 1 to about 10 mm (e.g.,about 2 to about 7 mm).

Turning to FIGS. 4A and 4B, there is illustrated an example of anoptional secondary shaping operation. In particular, the shaping ofarticles in accordance with the present invention envisions thepossibility of employing a secondary stamping operation, and moreparticularly a shear edge deformation step. The secondary step may beperformed under one or more elevated temperatures, but more typicallywill be conducted at or below room temperature (e.g., from about 0 toabout 20° C., and more specifically up to about 15° C.). Prior to thetime of the secondary shaping operation, typically the intermediate formwill be at least partially consolidated (e.g., through the heat involvedin the operations illustrated in FIGS. 3A and 3B). However, it ispossible that consolidation will occur during the secondary shapingoperation, particularly since sustained pressures for about 0.5 to about5 minutes (e.g., about 1.5 to 3 minutes) during the secondary shapingoperation may be on the order of about 50 to about 250 Bar, and morespecifically about 100 to about 200 Bar (e.g., about 175 Bar).Accordingly, in view of the above, it is possible that the use of thecarrier frame 26, the blank holder 38, or both, may be omitted. As withthe other examples herein, it will be appreciated upon review of theseteachings that the above is not intended to cover every scenario inwhich the present inventions may be employed. Variation of theparameters may be made depending upon the results sought, the size ofthe blank that is processed, the nature of the material that isprocessed, and other related considerations. For example, longer orshorter times may be employed, as may be higher or lower pressures thanthose recited in the above discussion.

One possible benefit of the secondary shaping operation will be thatadditional strain hardening (it being recognized that before or duringconsolidation at elevated temperatures, strain elongation of about 10 toabout 40% may be employed) can occur in the intermediate form during theshaping step, and will therefore impart improved mechanical propertiesto the shaped articles. By way of example, strain elongation be keptbelow about 15% and more preferably below 10%. Accordingly, it ispossible that the secondary shaping operation may occur usingdifferently dimensioned shaping tooling (which optionally may beconfigured to be cooled during shaping) than in the primary operation.It may also employ the same tooling as in the primary operation, but asa result of shrinkage or relaxation of the intermediate form after theprimary operation, a gap results at the tooling/intermediate forminterface, affording volume to enable additional deformation. In yetanother approach, there may be no gap, and the material of theintermediate form is thus further compressed between the tooling forachieving further consolidation, or local densification within a desiredregion. In another approach, the secondary operation is employed forpreserving the dimensions and geometry of the shaped intermediate formduring cooling. Any combination of the steps recited in this paragraphmay also be employed.

Thus, pursuant to FIGS. 4A and 4B, one or more tools 60, such as a toolthat incorporates at least one shear edge 62 may be substituted for atleast one of the shaping tools of FIGS. 3A and 3B. Optionally,alternative tooling 36′ carried in platen 46′ may be substituted aswell. It can be seen that the ability to deform the intermediate formwithout heating it for softening thermoplastic constituent materials isan advantage made possible by the present invention.

It can be seen that another of the benefits that may be possible usingthe present invention is the ability to stamp the shaped articles(whether symmetrical or asymmetrical in geometry) that require minimalor no additional finishing steps. This also offers a benefit of reducingsubsequent cutting operations. The stamping step may also employsuitable pressure so that consolidation of the intermediate form occursduring the stamping. It should be recognized that stamping need not onlybe cold stamping. Stamping a heated form at an elevated temperature isalso possible.

It is possible that when a plurality of stages are employed for shapingthe forms of the present invention a plurality of separate presses maybe employed. It is also possible to configure tooling for a single pressthat accomplishes the combination of functions performed in the separatestages.

The elegance in the simplicity of this approach is still furthermanifested by the ability to use a single apparatus for deforming a widerange of intermediate forms of different size, geometric, complexity,material characteristics, and the like, simply by the selection of anappropriate interchangeable biasing member (e.g., a spring). To thispoint, it has been recognized herein that selection of the appropriatebiasing member may be achieved by determining a threshold stress, (e.g.,a stress beyond which the elongated members of the intermediate formwill plastically deform unpredictably) and selecting the biasing memberso that it exerts only enough force upon the intermediate form (e.g., inthe periphery region) that lateral displacement of the intermediate formwill occur before the threshold stress is realized.

The manner of supporting the intermediate form so that it isdisplaceable during shaping can be achieved by any of a number ofalternative approaches as well. By way of example, one approach is toemploy about the periphery of the region for shaping with one or morephysical displacement resistors. For instance, the intermediate form mayinclude variations in topography, a surface protuberance, or the likewhich can offer a resistive force when coming into contact with anopposing member associated with the tooling. The resistor may bestructured so that it progressively pulls through the tooling upon athreshold force.

Another approach may be to apply at least a partially continuouslyvariable clamping force (e.g., by a mechanical, electromechanical, orelectromagnetic clamping mechanism), to the intermediate form whiledeforming the intermediate form. The clamping force can be cycled, forexample so that, while deformation occurs, the clamping force is brieflyreduced and during the brief reduction the intermediate form can bedisplaced, wherein upon reinstatement of the clamping force theintermediate form is restored to fix the periphery region. Theintermittent steps of applying a fixed clamping force and forcereduction can be repeated as desired in regular or irregular periods.

Without intending to be limited thereby, one specific example of thepresent invention involves an apparatus such as in FIG. 5. Again, aswith the other examples herein, it will be appreciated upon review ofthese teachings that the example is not intended to cover all scenariosin which the present inventions may be employed. Variation of theparameters may be made depending upon the results sought, the size ofthe blank that is processed, the nature of the material that isprocessed, and other related considerations. Six carbon steel springsare located about the apparatus for biasing the blank holder toward anintermediate form when disposed between a first and second shaping tool.Each spring is rated at 32.16 (N/mm) per cm—(that is, rate per mm percm). Given an original length, for each spring, L₀ of 130 mm, acompression spring constant is realized of 32.16 [N/(mm/cm)]/13[cm]=2.47 [N/mm]. Given each spring compresses by 76 mm, a forcecontributed by each spring is obtained of 76 mm×2.47 [N/mm]=188 [N].

This force is realized when, for instance, the intermediate form isshaped while at an elevated temperature. The total force (F) distributedover the form, which if contributed by the blank holder springs F=188×6[N]=1128 N.

Using this force, the apparatus can readily press out a deep draw depthof draw ratio (the relationship of depth to width of a part) of about0.1:10 to about 5:1 (e.g., about 1:1) on a relatively large blank (e.g.,about 350 to about 550 cm² in area) from a multilayer intermediate formmade of from about 14 to 34 layers of woven polypropylene sheet. It alsoacts to prevent reversion, not just prevent slip.

In this example, carrier frame dimensions are about 22.5 cm per side,with the perimeter wall defining the internal opening being about 13 mmwide. This presents an area of about 0.011 m². If the carrier were totake all this pressure alone, this equates to a pressure of 102 kPa or 1Bar. If it is assumed that the force also acts on all of the areacontacted by the blank holder, then the force acts over an area of 0.051m² and the pressure is actually 22.3 kPa or 0.22 Bar.

It should be appreciated that in one particular aspect of the presentinvention, many of the foregoing properties are the result of acombination of materials selection and processing conditions that resultin the preservation of substantial morphology (and specificallyorientation) within the elongated member component of the intermediateform throughout all processing steps until completion of the finishedarticle. Specifically, one approach of the present invention is to avoidany step of consolidating the intermediate form prior to thermoforming,stamping or other intermediate form shaping step. Prior materials wouldemploy a consolidation step prior to any such intermediate form shapingstep. However, such orientation of preservation is not mandatory formany of the novel embodiments disclosed herein. Accordingly, the skilledartisan will recognize that various of the prior art materials thatemploy a consolidation step prior to an intermediate form shaping stepmay still be employed for making composites within such embodiments. Inaddition, it is possible that multi-layer intermediate forms may beemployed with fewer than all of the layers having been processed formaintaining orientation.

Reference herein to “first” and “second” are not intended as limiting tocombinations that consist of only first and second items. Whereso-referenced, it is possible that the subject matter of the presentinvention may suitably incorporate third, fourth or more items.Reference to “elongated member” is not intended to foreclose coverage ofa plurality of elongated members. Except where stated, the use ofprocessing steps such as “consolidating” or “shaping” or theirconjugates do not require complete consolidation or shaping; a partialconsolidation or shaping is also contemplated. Moreover, the disclosureof “a” or “one” element or step is not intended to foreclose additionalelements or steps.

Unless stated otherwise, dimensions and geometries of the variousembodiments depicted herein are not intended to be restrictive of theinvention, and other dimensions or geometries are possible. Pluralstructural components step can be provided by a single integratedstructure or step. Alternatively, a single integrated structure stepmight be divided into separate plural components or steps. However, itis also possible that the functions are integrated into a singlecomponent or step.

In addition, while a feature of the present invention may have beendescribed in the context of only one of the illustrated embodiments,such feature may be combined with one or more other features of otherembodiments, for any given application. It will also be appreciated fromthe above that the fabrication of the unique structures herein and theoperation thereof also constitute processes in accordance with thepresent invention.

It is understood that the above description is intended to beillustrative and not restrictive. Many embodiments as well as manyapplications besides the examples provided will be apparent to those ofskill in the art upon reading the above description. The scope of theinvention should, therefore, be determined not with reference to theabove description, but should instead be determined with reference tothe appended claims, along with the full scope of equivalents to whichsuch claims are entitled. The disclosures of all articles andreferences, including patent applications and publications, areincorporated by reference for all purposes. The omission in thefollowing claims of any aspect of subject matter that is disclosedherein is not a disclaimer of such subject matter, nor should it beregarded that the inventors did not consider such subject matter to bepart of the disclosed inventive subject matter.

1. A process for forming a shaped three dimensional article, comprisingthe steps of: deforming an intermediate form that consists essentiallyof a plurality of thermoplastic elongated members while clamping theintermediate form during the deforming in such a way that while a forceis applied for deforming the intermediate form, the intermediate form isfree to move within a predetermined limit; and optionally, at leastpartially consolidating the thermoplastic elongated members of theintermediate form for forming a three dimensional article.
 2. A processaccording to claim 1, wherein the thermoplastic elongated members aretapes that include polypropylene.
 3. A process according to claims 1 or2, wherein the at least partially consolidating step occurs during thedeforming step.
 4. A process according to claims 1 through 3, whereinthe displaceable clamping is performed by a spring biased blank holder.5. A process according to claims 1 through 4, further comprising a stepof preloading the intermediate form in a carrier frame and maintainingthe intermediate form in the carrier frame during at least the deformingstep.
 6. The process according to any of claims 1 through 5, furthercomprising heating the intermediate form to a temperature such that acentral portion of the elongated members of the intermediate formremains below their melting point but soften sufficient for facilitatingdeforming and avoiding rupture of the elongated members during thedeforming.
 7. The process according to claim 6, wherein the elongatedmembers have an oriented molecular portion.
 8. The process according toclaim 7, wherein the temperature of the heating is maintained so thatorientation of the oriented portion of the elongated members issubstantially preserved throughout the deforming step.
 9. The processaccording to any of claims 1 through 8, further comprising a step ofshear edge stamping the form.
 10. The process according to claim 9,wherein the deforming step and the shear edge stamping step is performedusing a common press.
 11. The process according to claim 10, furthercomprising employing for the deforming step and the shear edge stampingstep at least two independently moveable tools.
 12. The processaccording to claim 11, further comprising locating the at least twoindependently moveable tools on the same side of the intermediate formprior to the deforming and stamping steps.
 13. The process according toclaim 11, further comprising locating the at least two independentlymoveable tools on opposing sides of the intermediate form prior to thedeforming and stamping steps.
 14. The process according to claim 9,wherein the deforming step and the shear edge stamping steps areperformed in separate presses.
 15. The process according to any ofclaims 1 through 14, further comprising varying the thickness of theintermediate form for forming a resulting three dimensional articlehaving a variable thickness.
 16. The process according to any of theclaims 1 through 16, wherein the intermediate form includes a pluralityof layers.
 17. A process for forming a shaped three dimensional article,comprising the steps of: deforming an intermediate form while clampingthe intermediate form during the deforming in such a way that while aforce is applied for deforming the intermediate form, the intermediateform is free to move within a predetermined limit; and at leastpartially consolidating the intermediate form; and optionally stampingthe intermediate form in a secondary forming operation.
 18. The processaccording to claim 17, wherein the stamping includes a shear edgestamping step.
 19. An apparatus for forming a three-dimensional article,comprising: a) a first tool for deforming an intermediate form at anelevated temperature; b) an optional second tool for stamping theintermediate form; and c) a holder for clamping the intermediate formduring deforming in such a way that while a force is applied fordeforming the intermediate form, the intermediate form is free to movewithin a predetermined limit.
 20. The apparatus of claim 19, wherein theholder includes a plurality of biasing members that bias the holder in adirection parallel to the direction of travel of the first tool in theapparatus.
 21. An article made according to any of the processes ofclaims 1 through 18.